Re: Speed improvements in ZFS

When I watch the activity leds of the disks on one of our ZFS servers, I notice there will be a burst of activity for 3 or 4 seconds, then no activity for a couple of seconds, then it repeats.
Is that normal?

Thanks,

joe


Joe McGuckin
ViaNet Communications

joe@via.net
650-207-0372 cell
650-213-1302 office
650-969-2124 fax



> On Aug 15, 2023, at 12:33 PM, Alexander Leidinger <Alexander@Leidinger.net> wrote:
> 
> Am 2023-08-15 14:41, schrieb Mateusz Guzik:
> 
>> With this in mind can you provide: sysctl kern.maxvnodes
>> vfs.wantfreevnodes vfs.freevnodes vfs.vnodes_created vfs.numvnodes
>> vfs.recycles_free vfs.recycles
> 
> After a reboot:
> kern.maxvnodes: 10485760
> vfs.wantfreevnodes: 2621440
> vfs.freevnodes: 24696
> vfs.vnodes_created: 1658162
> vfs.numvnodes: 173937
> vfs.recycles_free: 0
> vfs.recycles: 0
> 
>> Meanwhile if there is tons of recycles, you can damage control by
>> bumping kern.maxvnodes.
> 
> Looks like there are not much free directly after the reboot. I will check the values tomorrow after the periodic run again and maybe increase by 10 or 100 so see if it makes a difference.
> 
>> If this is not the problem you can use dtrace to figure it out.
> 
> dtrace-count on vnlru_read_freevnodes() and vnlru_free_locked()? Or something else?
> 
> Bye,
> Alexander.
> 
> -- 
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